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Microwave spectra and conformational studies of ethylamine from temperature dependent Raman spectra of xenon solutions and ab initio calculations
- Source :
- Journal of molecular structure
- Publication Year :
- 2014
-
Abstract
- FT-microwave spectroscopy was carried out where the trans conformer was identified to be the most stable conformer. Variable temperature (-60 to -100 degrees C) studies of the Raman spectra (4000-50 cm(-1)) of ethylamine, CH3CH2NH2 dissolved in liquefied xenon have been carried out. From these data both conformers have been identified and their relative stabilities obtained. The enthalpy difference has been determined to be 62 +/- 6 cm(-1) (0.746 +/- 0.072 kJ mol(-1)) with the trans conformer the more stable form. The percentage of the gauche conformer is estimated to be 60% at ambient temperature. The conformational stabilities have been predicted from ab initio calculations with the Moller-Plesset perturbation method to the second order (MP2(full)) and the fourth order (MP4(SDTQ)) as well as with density functional theory by the B3LYP method by utilizing a variety of basis sets. Vibrational assignments have been made for the observed bands which have been predicted by MP2(full)/6-31G(d) ab initio calculations which includes harmonic force fields, frequencies, infrared intensities, Raman activities and depolarization ratios for both conformers. The results are discussed and compared to the corresponding properties of some similar molecule. (C) 2014 Published by Elsevier B.V.
- Subjects :
- Organic Chemistry
Enthalpy
chemistry.chemical_element
Analytical Chemistry
Inorganic Chemistry
chemistry.chemical_compound
symbols.namesake
Chemistry
Xenon
chemistry
Computational chemistry
Ab initio quantum chemistry methods
symbols
Physical chemistry
Density functional theory
Ethylamine
Spectroscopy
Raman spectroscopy
Conformational isomerism
Subjects
Details
- Language :
- English
- ISSN :
- 00222860
- Database :
- OpenAIRE
- Journal :
- Journal of molecular structure
- Accession number :
- edsair.doi.dedup.....99df80b9b7e16cdf0f8fc0ec311f09de